udev/udevd.c

   1 /*
   2  * Copyright (C) 2004-2009 Kay Sievers <kay.sievers@vrfy.org>
   3  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
   4  * Copyright (C) 2009 Canonical Ltd.
   5  * Copyright (C) 2009 Scott James Remnant <scott@netsplit.com>
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation, either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <stddef.h>
  22 #include <signal.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <stdbool.h>
  28 #include <string.h>
  29 #include <ctype.h>
  30 #include <fcntl.h>
  31 #include <time.h>
  32 #include <getopt.h>
  33 #include <dirent.h>
  34 #include <sys/time.h>
  35 #include <sys/prctl.h>
  36 #include <sys/socket.h>
  37 #include <sys/signalfd.h>
  38 #include <sys/select.h>
  39 #include <sys/poll.h>
  40 #include <sys/wait.h>
  41 #include <sys/stat.h>
  42 #include <sys/ioctl.h>
  43 #include <sys/inotify.h>
  44
  45 #include "udev.h"
  46
  47 #define UDEVD_PRIORITY                  -4
  48 #define UDEV_PRIORITY                   -2
  49
  50 static bool debug;
  51
  52 static void log_fn(struct udev *udev, int priority,
  53                    const char *file, int line, const char *fn,
  54                    const char *format, va_list args)
  55 {
  56         if (debug) {
  57                 char buf[1024];
  58                 struct timeval tv;
  59                 struct timezone tz;
  60
  61                 vsnprintf(buf, sizeof(buf), format, args);
  62                 gettimeofday(&tv, &tz);
  63                 fprintf(stderr, "%llu.%06u [%u] %s: %s",
  64                         (unsigned long long) tv.tv_sec, (unsigned int) tv.tv_usec,
  65                         (int) getpid(), fn, buf);
  66         } else {
  67                 vsyslog(priority, format, args);
  68         }
  69 }
  70
  71 static bool debug_trace;
  72 static struct udev_rules *rules;
  73 static struct udev_queue_export *udev_queue_export;
  74 static struct udev_ctrl *udev_ctrl;
  75 static struct udev_monitor *monitor;
  76 static int worker_watch[2];
  77 static pid_t settle_pid;
  78 static bool stop_exec_queue;
  79 static bool reload_config;
  80 static int max_childs;
  81 static int childs;
  82 static struct udev_list_node event_list;
  83 static struct udev_list_node worker_list;
  84 static bool udev_exit;
  85 static volatile sig_atomic_t worker_exit;
  86
  87 enum poll_fd {
  88         FD_CONTROL,
  89         FD_NETLINK,
  90         FD_INOTIFY,
  91         FD_SIGNAL,
  92         FD_WORKER,
  93 };
  94
  95 static struct pollfd pfd[] = {
  96         [FD_NETLINK] = { .events = POLLIN },
  97         [FD_WORKER] =  { .events = POLLIN },
  98         [FD_SIGNAL] =  { .events = POLLIN },
  99         [FD_INOTIFY] = { .events = POLLIN },
 100         [FD_CONTROL] = { .events = POLLIN },
 101 };
 102
 103 enum event_state {
 104         EVENT_UNDEF,
 105         EVENT_QUEUED,
 106         EVENT_RUNNING,
 107 };
 108
 109 struct event {
 110         struct udev_list_node node;
 111         struct udev *udev;
 112         struct udev_device *dev;
 113         enum event_state state;
 114         int exitcode;
 115         unsigned long long int delaying_seqnum;
 116         unsigned long long int seqnum;
 117         const char *devpath;
 118         size_t devpath_len;
 119         const char *devpath_old;
 120 };
 121
 122 static struct event *node_to_event(struct udev_list_node *node)
 123 {
 124         char *event;
 125
 126         event = (char *)node;
 127         event -= offsetof(struct event, node);
 128         return (struct event *)event;
 129 }
 130
 131 enum worker_state {
 132         WORKER_UNDEF,
 133         WORKER_RUNNING,
 134         WORKER_IDLE,
 135         WORKER_KILLED,
 136 };
 137
 138 struct worker {
 139         struct udev_list_node node;
 140         struct udev *udev;
 141         int refcount;
 142         pid_t pid;
 143         struct udev_monitor *monitor;
 144         enum worker_state state;
 145         struct event *event;
 146 };
 147
 148 /* passed from worker to main process */
 149 struct worker_message {
 150         pid_t pid;
 151         int exitcode;
 152 };
 153
 154 static struct worker *node_to_worker(struct udev_list_node *node)
 155 {
 156         char *worker;
 157
 158         worker = (char *)node;
 159         worker -= offsetof(struct worker, node);
 160         return (struct worker *)worker;
 161 }
 162
 163 static void event_queue_delete(struct event *event)
 164 {
 165         udev_list_node_remove(&event->node);
 166
 167         /* mark as failed, if "add" event returns non-zero */
 168         if (event->exitcode != 0 && strcmp(udev_device_get_action(event->dev), "add") == 0)
 169                 udev_queue_export_device_failed(udev_queue_export, event->dev);
 170         else
 171                 udev_queue_export_device_finished(udev_queue_export, event->dev);
 172
 173         info(event->udev, "seq %llu done with %i\n", udev_device_get_seqnum(event->dev), event->exitcode);
 174         udev_device_unref(event->dev);
 175         free(event);
 176 }
 177
 178 static void event_sig_handler(int signum)
 179 {
 180         switch (signum) {
 181         case SIGALRM:
 182                 _exit(1);
 183                 break;
 184         case SIGTERM:
 185                 worker_exit = true;
 186                 break;
 187         }
 188 }
 189
 190 static struct worker *worker_ref(struct worker *worker)
 191 {
 192         worker->refcount++;
 193         return worker;
 194 }
 195
 196 static void worker_unref(struct worker *worker)
 197 {
 198         worker->refcount--;
 199         if (worker->refcount > 0)
 200                 return;
 201
 202         udev_list_node_remove(&worker->node);
 203         udev_monitor_unref(worker->monitor);
 204         childs--;
 205         info(worker->udev, "worker [%u] cleaned up\n", worker->pid);
 206         free(worker);
 207 }
 208
 209 static void worker_new(struct event *event)
 210 {
 211         struct worker *worker;
 212         struct udev_monitor *worker_monitor;
 213         pid_t pid;
 214         struct sigaction act;
 215
 216         /* listen for new events */
 217         worker_monitor = udev_monitor_new_from_netlink(event->udev, NULL);
 218         if (worker_monitor == NULL)
 219                 return;
 220         /* allow the main daemon netlink address to send devices to the worker */
 221         udev_monitor_allow_unicast_sender(worker_monitor, monitor);
 222         udev_monitor_enable_receiving(worker_monitor);
 223         util_set_fd_cloexec(udev_monitor_get_fd(worker_monitor));
 224
 225         worker = calloc(1, sizeof(struct worker));
 226         if (worker == NULL)
 227                 return;
 228         /* worker + event reference */
 229         worker->refcount = 2;
 230         worker->udev = event->udev;
 231
 232         pid = fork();
 233         switch (pid) {
 234         case 0: {
 235                 sigset_t sigmask;
 236                 struct udev_device *dev;
 237                 struct pollfd pmon = {
 238                         .fd = udev_monitor_get_fd(worker_monitor),
 239                         .events = POLLIN,
 240                 };
 241
 242                 udev_queue_export_unref(udev_queue_export);
 243                 udev_monitor_unref(monitor);
 244                 udev_ctrl_unref(udev_ctrl);
 245                 close(pfd[FD_SIGNAL].fd);
 246                 close(worker_watch[READ_END]);
 247                 udev_log_close();
 248                 udev_log_init("udevd-work");
 249                 setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
 250
 251                 /* set signal handlers */
 252                 memset(&act, 0x00, sizeof(act));
 253                 act.sa_handler = event_sig_handler;
 254                 sigemptyset (&act.sa_mask);
 255                 act.sa_flags = 0;
 256                 sigaction(SIGTERM, &act, NULL);
 257                 sigaction(SIGALRM, &act, NULL);
 258
 259                 /* unblock SIGALRM */
 260                 sigfillset(&sigmask);
 261                 sigdelset(&sigmask, SIGALRM);
 262                 sigprocmask(SIG_SETMASK, &sigmask, NULL);
 263                 /* SIGTERM is unblocked in ppoll() */
 264                 sigdelset(&sigmask, SIGTERM);
 265
 266                 /* request TERM signal if parent exits */
 267                 prctl(PR_SET_PDEATHSIG, SIGTERM);
 268
 269                 /* initial device */
 270                 dev = event->dev;
 271
 272                 do {
 273                         struct udev_event *udev_event;
 274                         struct worker_message msg = {};
 275                         int err;
 276                         int failed = 0;
 277
 278                         info(event->udev, "seq %llu running\n", udev_device_get_seqnum(dev));
 279                         udev_event = udev_event_new(dev);
 280                         if (udev_event == NULL)
 281                                 _exit(3);
 282
 283                         /* set timeout to prevent hanging processes */
 284                         alarm(UDEV_EVENT_TIMEOUT);
 285
 286                         /* apply rules, create node, symlinks */
 287                         err = udev_event_execute_rules(udev_event, rules);
 288
 289                         /* rules may change/disable the timeout */
 290                         if (udev_device_get_event_timeout(dev) >= 0)
 291                                 alarm(udev_device_get_event_timeout(dev));
 292
 293                         /* execute RUN= */
 294                         if (err == 0 && !udev_event->ignore_device && udev_get_run(udev_event->udev))
 295                                 failed = udev_event_execute_run(udev_event);
 296
 297                         /* reset alarm */
 298                         alarm(0);
 299
 300                         /* apply/restore inotify watch */
 301                         if (err == 0 && udev_event->inotify_watch) {
 302                                 udev_watch_begin(udev_event->udev, dev);
 303                                 udev_device_update_db(dev);
 304                         }
 305
 306                         /* send processed event back to libudev listeners */
 307                         udev_monitor_send_device(worker_monitor, NULL, dev);
 308
 309                         /* send back the result of the event execution */
 310                         if (err != 0)
 311                                 msg.exitcode = err;
 312                         else if (failed != 0)
 313                                 msg.exitcode = failed;
 314                         msg.pid = getpid();
 315                         send(worker_watch[WRITE_END], &msg, sizeof(struct worker_message), 0);
 316
 317                         info(event->udev, "seq %llu processed with %i\n", udev_device_get_seqnum(dev), err);
 318                         udev_event_unref(udev_event);
 319                         udev_device_unref(dev);
 320                         dev = NULL;
 321
 322                         /* wait for more device messages or signal from udevd */
 323                         while (!worker_exit) {
 324                                 int fdcount;
 325
 326                                 fdcount = ppoll(&pmon, 1, NULL, &sigmask);
 327                                 if (fdcount < 0)
 328                                         continue;
 329
 330                                 if (pmon.revents & POLLIN) {
 331                                         dev = udev_monitor_receive_device(worker_monitor);
 332                                         if (dev != NULL)
 333                                                 break;
 334                                 }
 335                         }
 336                 } while (dev != NULL);
 337
 338                 udev_monitor_unref(worker_monitor);
 339                 udev_log_close();
 340                 exit(0);
 341         }
 342         case -1:
 343                 udev_monitor_unref(worker_monitor);
 344                 event->state = EVENT_QUEUED;
 345                 free(worker);
 346                 err(event->udev, "fork of child failed: %m\n");
 347                 break;
 348         default:
 349                 /* close monitor, but keep address around */
 350                 udev_monitor_disconnect(worker_monitor);
 351                 worker->monitor = worker_monitor;
 352                 worker->pid = pid;
 353                 worker->state = WORKER_RUNNING;
 354                 worker->event = event;
 355                 event->state = EVENT_RUNNING;
 356                 udev_list_node_append(&worker->node, &worker_list);
 357                 childs++;
 358                 info(event->udev, "seq %llu forked new worker [%u]\n", udev_device_get_seqnum(event->dev), pid);
 359                 break;
 360         }
 361 }
 362
 363 static void event_run(struct event *event)
 364 {
 365         struct udev_list_node *loop;
 366
 367         udev_list_node_foreach(loop, &worker_list) {
 368                 struct worker *worker = node_to_worker(loop);
 369                 ssize_t count;
 370
 371                 if (worker->state != WORKER_IDLE)
 372                         continue;
 373
 374                 count = udev_monitor_send_device(monitor, worker->monitor, event->dev);
 375                 if (count < 0) {
 376                         err(event->udev, "worker [%u] did not accept message %zi (%m), kill it\n", worker->pid, count);
 377                         kill(worker->pid, SIGKILL);
 378                         worker->state = WORKER_KILLED;
 379                         continue;
 380                 }
 381                 worker_ref(worker);
 382                 worker->event = event;
 383                 worker->state = WORKER_RUNNING;
 384                 event->state = EVENT_RUNNING;
 385                 return;
 386         }
 387
 388         if (childs >= max_childs) {
 389                 info(event->udev, "maximum number (%i) of childs reached\n", childs);
 390                 return;
 391         }
 392
 393         /* start new worker and pass initial device */
 394         worker_new(event);
 395 }
 396
 397 static void event_queue_insert(struct udev_device *dev)
 398 {
 399         struct event *event;
 400
 401         event = calloc(1, sizeof(struct event));
 402         if (event == NULL)
 403                 return;
 404
 405         event->udev = udev_device_get_udev(dev);
 406         event->dev = dev;
 407         event->seqnum = udev_device_get_seqnum(dev);
 408         event->devpath = udev_device_get_devpath(dev);
 409         event->devpath_len = strlen(event->devpath);
 410         event->devpath_old = udev_device_get_devpath_old(dev);
 411
 412         udev_queue_export_device_queued(udev_queue_export, dev);
 413         info(event->udev, "seq %llu queued, '%s' '%s'\n", udev_device_get_seqnum(dev),
 414              udev_device_get_action(dev), udev_device_get_subsystem(dev));
 415
 416         event->state = EVENT_QUEUED;
 417         udev_list_node_append(&event->node, &event_list);
 418
 419         /* run all events with a timeout set immediately */
 420         if (udev_device_get_timeout(dev) > 0) {
 421                 worker_new(event);
 422                 return;
 423         }
 424 }
 425
 426 static void worker_kill(struct udev *udev, int retain)
 427 {
 428         struct udev_list_node *loop;
 429         int max;
 430
 431         if (childs <= retain)
 432                 return;
 433
 434         max = childs - retain;
 435
 436         udev_list_node_foreach(loop, &worker_list) {
 437                 struct worker *worker = node_to_worker(loop);
 438
 439                 if (max-- <= 0)
 440                         break;
 441
 442                 if (worker->state == WORKER_KILLED)
 443                         continue;
 444
 445                 worker->state = WORKER_KILLED;
 446                 kill(worker->pid, SIGTERM);
 447         }
 448 }
 449
 450 static int mem_size_mb(void)
 451 {
 452         FILE *f;
 453         char buf[4096];
 454         long int memsize = -1;
 455
 456         f = fopen("/proc/meminfo", "r");
 457         if (f == NULL)
 458                 return -1;
 459
 460         while (fgets(buf, sizeof(buf), f) != NULL) {
 461                 long int value;
 462
 463                 if (sscanf(buf, "MemTotal: %ld kB", &value) == 1) {
 464                         memsize = value / 1024;
 465                         break;
 466                 }
 467         }
 468
 469         fclose(f);
 470         return memsize;
 471 }
 472
 473 /* lookup event for identical, parent, child device */
 474 static int devpath_busy(struct event *event)
 475 {
 476         struct udev_list_node *loop;
 477         size_t common;
 478
 479         /* check if queue contains events we depend on */
 480         udev_list_node_foreach(loop, &event_list) {
 481                 struct event *loop_event = node_to_event(loop);
 482
 483                 /* we already found a later event, earlier can not block us, no need to check again */
 484                 if (loop_event->seqnum < event->delaying_seqnum)
 485                         continue;
 486
 487                 /* event we checked earlier still exists, no need to check again */
 488                 if (loop_event->seqnum == event->delaying_seqnum)
 489                         return 2;
 490
 491                 /* found ourself, no later event can block us */
 492                 if (loop_event->seqnum >= event->seqnum)
 493                         break;
 494
 495                 /* check our old name */
 496                 if (event->devpath_old != NULL)
 497                         if (strcmp(loop_event->devpath, event->devpath_old) == 0) {
 498                                 event->delaying_seqnum = loop_event->seqnum;
 499                                 return 3;
 500                         }
 501
 502                 /* compare devpath */
 503                 common = MIN(loop_event->devpath_len, event->devpath_len);
 504
 505                 /* one devpath is contained in the other? */
 506                 if (memcmp(loop_event->devpath, event->devpath, common) != 0)
 507                         continue;
 508
 509                 /* identical device event found */
 510                 if (loop_event->devpath_len == event->devpath_len) {
 511                         event->delaying_seqnum = loop_event->seqnum;
 512                         return 4;
 513                 }
 514
 515                 /* parent device event found */
 516                 if (event->devpath[common] == '/') {
 517                         event->delaying_seqnum = loop_event->seqnum;
 518                         return 5;
 519                 }
 520
 521                 /* child device event found */
 522                 if (loop_event->devpath[common] == '/') {
 523                         event->delaying_seqnum = loop_event->seqnum;
 524                         return 6;
 525                 }
 526
 527                 /* no matching device */
 528                 continue;
 529         }
 530
 531         return 0;
 532 }
 533
 534 static void events_start(struct udev *udev)
 535 {
 536         struct udev_list_node *loop;
 537
 538         udev_list_node_foreach(loop, &event_list) {
 539                 struct event *event = node_to_event(loop);
 540
 541                 if (event->state != EVENT_QUEUED)
 542                         continue;
 543
 544                 /* do not start event if parent or child event is still running */
 545                 if (devpath_busy(event) != 0) {
 546                         dbg(udev, "delay seq %llu (%s)\n", event->seqnum, event->devpath);
 547                         continue;
 548                 }
 549
 550                 event_run(event);
 551         }
 552 }
 553
 554 static void worker_returned(void)
 555 {
 556         while (1) {
 557                 struct worker_message msg;
 558                 ssize_t size;
 559                 struct udev_list_node *loop;
 560
 561                 size = recv(pfd[FD_WORKER].fd, &msg, sizeof(struct worker_message), MSG_DONTWAIT);
 562                 if (size != sizeof(struct worker_message))
 563                         break;
 564
 565                 /* lookup worker who sent the signal */
 566                 udev_list_node_foreach(loop, &worker_list) {
 567                         struct worker *worker = node_to_worker(loop);
 568
 569                         if (worker->pid != msg.pid)
 570                                 continue;
 571
 572                         /* worker returned */
 573                         worker->event->exitcode = msg.exitcode;
 574                         event_queue_delete(worker->event);
 575                         worker->event = NULL;
 576                         if (worker->state != WORKER_KILLED)
 577                                 worker->state = WORKER_IDLE;
 578                         worker_unref(worker);
 579                         break;
 580                 }
 581         }
 582 }
 583
 584 /* receive the udevd message from userspace */
 585 static void handle_ctrl_msg(struct udev_ctrl *uctrl)
 586 {
 587         struct udev *udev = udev_ctrl_get_udev(uctrl);
 588         struct udev_ctrl_msg *ctrl_msg;
 589         const char *str;
 590         int i;
 591
 592         ctrl_msg = udev_ctrl_receive_msg(uctrl);
 593         if (ctrl_msg == NULL)
 594                 return;
 595
 596         i = udev_ctrl_get_set_log_level(ctrl_msg);
 597         if (i >= 0) {
 598                 info(udev, "udevd message (SET_LOG_PRIORITY) received, log_priority=%i\n", i);
 599                 udev_set_log_priority(udev, i);
 600                 worker_kill(udev, 0);
 601         }
 602
 603         if (udev_ctrl_get_stop_exec_queue(ctrl_msg) > 0) {
 604                 info(udev, "udevd message (STOP_EXEC_QUEUE) received\n");
 605                 stop_exec_queue = true;
 606         }
 607
 608         if (udev_ctrl_get_start_exec_queue(ctrl_msg) > 0) {
 609                 info(udev, "udevd message (START_EXEC_QUEUE) received\n");
 610                 stop_exec_queue = false;
 611         }
 612
 613         if (udev_ctrl_get_reload_rules(ctrl_msg) > 0) {
 614                 info(udev, "udevd message (RELOAD_RULES) received\n");
 615                 reload_config = true;
 616         }
 617
 618         str = udev_ctrl_get_set_env(ctrl_msg);
 619         if (str != NULL) {
 620                 char *key;
 621
 622                 key = strdup(str);
 623                 if (key != NULL) {
 624                         char *val;
 625
 626                         val = strchr(key, '=');
 627                         if (val != NULL) {
 628                                 val[0] = '\0';
 629                                 val = &val[1];
 630                                 if (val[0] == '\0') {
 631                                         info(udev, "udevd message (ENV) received, unset '%s'\n", key);
 632                                         udev_add_property(udev, key, NULL);
 633                                 } else {
 634                                         info(udev, "udevd message (ENV) received, set '%s=%s'\n", key, val);
 635                                         udev_add_property(udev, key, val);
 636                                 }
 637                         } else {
 638                                 err(udev, "wrong key format '%s'\n", key);
 639                         }
 640                         free(key);
 641                 }
 642                 worker_kill(udev, 0);
 643         }
 644
 645         i = udev_ctrl_get_set_max_childs(ctrl_msg);
 646         if (i >= 0) {
 647                 info(udev, "udevd message (SET_MAX_CHILDS) received, max_childs=%i\n", i);
 648                 max_childs = i;
 649         }
 650
 651         settle_pid = udev_ctrl_get_settle(ctrl_msg);
 652         if (settle_pid > 0) {
 653                 info(udev, "udevd message (SETTLE) received\n");
 654                 kill(settle_pid, SIGUSR1);
 655                 settle_pid = 0;
 656         }
 657         udev_ctrl_msg_unref(ctrl_msg);
 658 }
 659
 660 /* read inotify messages */
 661 static int handle_inotify(struct udev *udev)
 662 {
 663         ssize_t nbytes, pos;
 664         char *buf;
 665         struct inotify_event *ev;
 666
 667         if ((ioctl(pfd[FD_INOTIFY].fd, FIONREAD, &nbytes) < 0) || (nbytes <= 0))
 668                 return 0;
 669
 670         buf = malloc(nbytes);
 671         if (buf == NULL) {
 672                 err(udev, "error getting buffer for inotify\n");
 673                 return -1;
 674         }
 675
 676         nbytes = read(pfd[FD_INOTIFY].fd, buf, nbytes);
 677
 678         for (pos = 0; pos < nbytes; pos += sizeof(struct inotify_event) + ev->len) {
 679                 struct udev_device *dev;
 680
 681                 ev = (struct inotify_event *)(buf + pos);
 682                 if (ev->len) {
 683                         dbg(udev, "inotify event: %x for %s\n", ev->mask, ev->name);
 684                         reload_config = true;
 685                         continue;
 686                 }
 687
 688                 dev = udev_watch_lookup(udev, ev->wd);
 689                 if (dev != NULL) {
 690                         dbg(udev, "inotify event: %x for %s\n", ev->mask, udev_device_get_devnode(dev));
 691                         if (ev->mask & IN_CLOSE_WRITE) {
 692                                 char filename[UTIL_PATH_SIZE];
 693                                 int fd;
 694
 695                                 info(udev, "device %s closed, synthesising 'change'\n", udev_device_get_devnode(dev));
 696                                 util_strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
 697                                 fd = open(filename, O_WRONLY);
 698                                 if (fd < 0 || write(fd, "change", 6) < 0)
 699                                         info(udev, "error writing uevent: %m\n");
 700                                 close(fd);
 701                         }
 702                         if (ev->mask & IN_IGNORED)
 703                                 udev_watch_end(udev, dev);
 704
 705                         udev_device_unref(dev);
 706                 }
 707
 708         }
 709
 710         free(buf);
 711         return 0;
 712 }
 713
 714 static void handle_signal(struct udev *udev, int signo)
 715 {
 716         switch (signo) {
 717         case SIGINT:
 718         case SIGTERM:
 719                 udev_exit = true;
 720                 break;
 721         case SIGCHLD:
 722                 while (1) {
 723                         pid_t pid;
 724                         int status;
 725                         struct udev_list_node *loop, *tmp;
 726
 727                         pid = waitpid(-1, &status, WNOHANG);
 728                         if (pid <= 0)
 729                                 break;
 730
 731                         udev_list_node_foreach_safe(loop, tmp, &worker_list) {
 732                                 struct worker *worker = node_to_worker(loop);
 733
 734                                 if (worker->pid != pid)
 735                                         continue;
 736
 737                                 info(udev, "worker [%u] exit\n", pid);
 738                                 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 739                                         err(udev, "worker [%u] unexpectedly returned with status 0x%04x\n", pid, status);
 740                                         if (worker->event != NULL) {
 741                                                 err(udev, "worker [%u] failed while handling '%s'\n", pid, worker->event->devpath);
 742                                                 worker->event->exitcode = -32;
 743                                                 event_queue_delete(worker->event);
 744                                                 /* drop reference from running event */
 745                                                 worker_unref(worker);
 746                                         }
 747                                 }
 748                                 worker_unref(worker);
 749                                 break;
 750                         }
 751                 }
 752                 break;
 753         case SIGHUP:
 754                 reload_config = true;
 755                 break;
 756         }
 757 }
 758
 759 static void startup_log(struct udev *udev)
 760 {
 761         FILE *f;
 762         char path[UTIL_PATH_SIZE];
 763         struct stat statbuf;
 764
 765         f = fopen("/dev/kmsg", "w");
 766         if (f != NULL)
 767                 fprintf(f, "<6>udev: starting version " VERSION "\n");
 768
 769         util_strscpyl(path, sizeof(path), udev_get_sys_path(udev), "/class/mem/null", NULL);
 770         if (lstat(path, &statbuf) == 0 && S_ISDIR(statbuf.st_mode)) {
 771                 const char *depr_str =
 772                         "udev: missing sysfs features; please update the kernel "
 773                         "or disable the kernel's CONFIG_SYSFS_DEPRECATED option; "
 774                         "udev may fail to work correctly";
 775
 776                 if (f != NULL)
 777                         fprintf(f, "<3>%s\n", depr_str);
 778                 err(udev, "%s\n", depr_str);
 779                 sleep(3);
 780         }
 781
 782         if (f != NULL)
 783                 fclose(f);
 784 }
 785
 786 int main(int argc, char *argv[])
 787 {
 788         struct udev *udev;
 789         int fd;
 790         sigset_t mask;
 791         const char *value;
 792         int daemonize = false;
 793         int resolve_names = 1;
 794         static const struct option options[] = {
 795                 { "daemon", no_argument, NULL, 'd' },
 796                 { "debug-trace", no_argument, NULL, 't' },
 797                 { "debug", no_argument, NULL, 'D' },
 798                 { "help", no_argument, NULL, 'h' },
 799                 { "version", no_argument, NULL, 'V' },
 800                 { "resolve-names", required_argument, NULL, 'N' },
 801                 {}
 802         };
 803         int rc = 1;
 804
 805         udev = udev_new();
 806         if (udev == NULL)
 807                 goto exit;
 808
 809         udev_log_init("udevd");
 810         udev_set_log_fn(udev, log_fn);
 811         info(udev, "version %s\n", VERSION);
 812         udev_selinux_init(udev);
 813
 814         while (1) {
 815                 int option;
 816
 817                 option = getopt_long(argc, argv, "dDthV", options, NULL);
 818                 if (option == -1)
 819                         break;
 820
 821                 switch (option) {
 822                 case 'd':
 823                         daemonize = true;
 824                         break;
 825                 case 't':
 826                         debug_trace = true;
 827                         break;
 828                 case 'D':
 829                         debug = true;
 830                         if (udev_get_log_priority(udev) < LOG_INFO)
 831                                 udev_set_log_priority(udev, LOG_INFO);
 832                         break;
 833                 case 'N':
 834                         if (strcmp (optarg, "early") == 0) {
 835                                 resolve_names = 1;
 836                         } else if (strcmp (optarg, "late") == 0) {
 837                                 resolve_names = 0;
 838                         } else if (strcmp (optarg, "never") == 0) {
 839                                 resolve_names = -1;
 840                         } else {
 841                                 fprintf(stderr, "resolve-names must be early, late or never\n");
 842                                 err(udev, "resolve-names must be early, late or never\n");
 843                                 goto exit;
 844                         }
 845                         break;
 846                 case 'h':
 847                         printf("Usage: udevd [--help] [--daemon] [--debug-trace] [--debug] "
 848                                "[--resolve-names=early|late|never] [--version]\n");
 849                         goto exit;
 850                 case 'V':
 851                         printf("%s\n", VERSION);
 852                         goto exit;
 853                 default:
 854                         goto exit;
 855                 }
 856         }
 857
 858         if (getuid() != 0) {
 859                 fprintf(stderr, "root privileges required\n");
 860                 err(udev, "root privileges required\n");
 861                 goto exit;
 862         }
 863
 864         /* make sure std{in,out,err} fd's are in a sane state */
 865         fd = open("/dev/null", O_RDWR);
 866         if (fd < 0) {
 867                 fprintf(stderr, "cannot open /dev/null\n");
 868                 err(udev, "cannot open /dev/null\n");
 869         }
 870         if (write(STDOUT_FILENO, 0, 0) < 0)
 871                 dup2(fd, STDOUT_FILENO);
 872         if (write(STDERR_FILENO, 0, 0) < 0)
 873                 dup2(fd, STDERR_FILENO);
 874
 875         /* init control socket, bind() ensures, that only one udevd instance is running */
 876         udev_ctrl = udev_ctrl_new_from_socket(udev, UDEV_CTRL_SOCK_PATH);
 877         if (udev_ctrl == NULL) {
 878                 fprintf(stderr, "error initializing control socket");
 879                 err(udev, "error initializing udevd socket");
 880                 rc = 1;
 881                 goto exit;
 882         }
 883         if (udev_ctrl_enable_receiving(udev_ctrl) < 0) {
 884                 fprintf(stderr, "error binding control socket, seems udevd is already running\n");
 885                 err(udev, "error binding control socket, seems udevd is already running\n");
 886                 rc = 1;
 887                 goto exit;
 888         }
 889         pfd[FD_CONTROL].fd = udev_ctrl_get_fd(udev_ctrl);
 890
 891         monitor = udev_monitor_new_from_netlink(udev, "kernel");
 892         if (monitor == NULL || udev_monitor_enable_receiving(monitor) < 0) {
 893                 fprintf(stderr, "error initializing netlink socket\n");
 894                 err(udev, "error initializing netlink socket\n");
 895                 rc = 3;
 896                 goto exit;
 897         }
 898         udev_monitor_set_receive_buffer_size(monitor, 128*1024*1024);
 899         pfd[FD_NETLINK].fd = udev_monitor_get_fd(monitor);
 900
 901         pfd[FD_INOTIFY].fd = udev_watch_init(udev);
 902         if (pfd[FD_INOTIFY].fd < 0) {
 903                 fprintf(stderr, "error initializing inotify\n");
 904                 err(udev, "error initializing inotify\n");
 905                 rc = 4;
 906                 goto exit;
 907         }
 908
 909         if (udev_get_rules_path(udev) != NULL) {
 910                 inotify_add_watch(pfd[FD_INOTIFY].fd, udev_get_rules_path(udev),
 911                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 912         } else {
 913                 char filename[UTIL_PATH_SIZE];
 914
 915                 inotify_add_watch(pfd[FD_INOTIFY].fd, LIBEXECDIR "/rules.d",
 916                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 917                 inotify_add_watch(pfd[FD_INOTIFY].fd, SYSCONFDIR "/udev/rules.d",
 918                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 919
 920                 /* watch dynamic rules directory */
 921                 util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/rules.d", NULL);
 922                 inotify_add_watch(pfd[FD_INOTIFY].fd, filename,
 923                                   IN_CREATE | IN_DELETE | IN_MOVE | IN_CLOSE_WRITE);
 924         }
 925         udev_watch_restore(udev);
 926
 927         /* block and listen to all signals on signalfd */
 928         sigfillset(&mask);
 929         sigprocmask(SIG_SETMASK, &mask, NULL);
 930         pfd[FD_SIGNAL].fd = signalfd(-1, &mask, 0);
 931         if (pfd[FD_SIGNAL].fd < 0) {
 932                 fprintf(stderr, "error getting signalfd\n");
 933                 err(udev, "error getting signalfd\n");
 934                 rc = 5;
 935                 goto exit;
 936         }
 937
 938         /* unnamed socket from workers to the main daemon */
 939         if (socketpair(AF_LOCAL, SOCK_DGRAM, 0, worker_watch) < 0) {
 940                 fprintf(stderr, "error getting socketpair\n");
 941                 err(udev, "error getting socketpair\n");
 942                 rc = 6;
 943                 goto exit;
 944         }
 945         pfd[FD_WORKER].fd = worker_watch[READ_END];
 946         util_set_fd_cloexec(worker_watch[WRITE_END]);
 947
 948         rules = udev_rules_new(udev, resolve_names);
 949         if (rules == NULL) {
 950                 err(udev, "error reading rules\n");
 951                 goto exit;
 952         }
 953
 954         udev_queue_export = udev_queue_export_new(udev);
 955         if (udev_queue_export == NULL) {
 956                 err(udev, "error creating queue file\n");
 957                 goto exit;
 958         }
 959
 960         if (daemonize) {
 961                 pid_t pid;
 962
 963                 pid = fork();
 964                 switch (pid) {
 965                 case 0:
 966                         break;
 967                 case -1:
 968                         err(udev, "fork of daemon failed: %m\n");
 969                         rc = 4;
 970                         goto exit;
 971                 default:
 972                         rc = 0;
 973                         goto exit;
 974                 }
 975         }
 976
 977         startup_log(udev);
 978
 979         /* redirect std{out,err} */
 980         if (!debug && !debug_trace) {
 981                 dup2(fd, STDIN_FILENO);
 982                 dup2(fd, STDOUT_FILENO);
 983                 dup2(fd, STDERR_FILENO);
 984         }
 985         if (fd > STDERR_FILENO)
 986                 close(fd);
 987
 988         /* set scheduling priority for the daemon */
 989         setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
 990
 991         chdir("/");
 992         umask(022);
 993         setsid();
 994
 995         /* OOM_DISABLE == -17 */
 996         fd = open("/proc/self/oom_adj", O_RDWR);
 997         if (fd < 0) {
 998                 err(udev, "error disabling OOM: %m\n");
 999         } else {
1000                 write(fd, "-17", 3);
1001                 close(fd);
1002         }
1003
1004         /* in trace mode run one event after the other */
1005         if (debug_trace) {
1006                 max_childs = 1;
1007         } else {
1008                 int memsize = mem_size_mb();
1009
1010                 if (memsize > 0)
1011                         max_childs = 128 + (memsize / 8);
1012                 else
1013                         max_childs = 128;
1014         }
1015
1016         /* possibly overwrite maximum limit of executed events */
1017         value = getenv("UDEVD_MAX_CHILDS");
1018         if (value)
1019                 max_childs = strtoul(value, NULL, 10);
1020         info(udev, "initialize max_childs to %u\n", max_childs);
1021
1022         udev_list_init(&event_list);
1023         udev_list_init(&worker_list);
1024
1025         while (!udev_exit) {
1026                 int fdcount;
1027                 int timeout;
1028
1029                 /* set timeout to kill idle workers */
1030                 if (udev_list_is_empty(&event_list) && childs > 2)
1031                         timeout = 3 * 1000;
1032                 else
1033                         timeout = -1;
1034                 /* wait for events */
1035                 fdcount = poll(pfd, ARRAY_SIZE(pfd), timeout);
1036                 if (fdcount < 0)
1037                         continue;
1038
1039                 /* timeout - kill idle workers */
1040                 if (fdcount == 0)
1041                         worker_kill(udev, 2);
1042
1043                 /* event has finished */
1044                 if (pfd[FD_WORKER].revents & POLLIN)
1045                         worker_returned();
1046
1047                 /* get kernel uevent */
1048                 if (pfd[FD_NETLINK].revents & POLLIN) {
1049                         struct udev_device *dev;
1050
1051                         dev = udev_monitor_receive_device(monitor);
1052                         if (dev != NULL)
1053                                 event_queue_insert(dev);
1054                         else
1055                                 udev_device_unref(dev);
1056                 }
1057
1058                 /* start new events */
1059                 if (!udev_list_is_empty(&event_list) && !stop_exec_queue)
1060                         events_start(udev);
1061
1062                 /* get signal */
1063                 if (pfd[FD_SIGNAL].revents & POLLIN) {
1064                         struct signalfd_siginfo fdsi;
1065                         ssize_t size;
1066
1067                         size = read(pfd[FD_SIGNAL].fd, &fdsi, sizeof(struct signalfd_siginfo));
1068                         if (size == sizeof(struct signalfd_siginfo))
1069                                 handle_signal(udev, fdsi.ssi_signo);
1070                 }
1071
1072                 /* device node and rules directory inotify watch */
1073                 if (pfd[FD_INOTIFY].revents & POLLIN)
1074                         handle_inotify(udev);
1075
1076                 /*
1077                  * get control message
1078                  *
1079                  * This needs to be after the inotify handling, to make sure,
1080                  * that the settle signal is send back after the possibly generated
1081                  * "change" events by the inotify device node watch.
1082                  */
1083                 if (pfd[FD_CONTROL].revents & POLLIN)
1084                         handle_ctrl_msg(udev_ctrl);
1085
1086                 /* rules changed, set by inotify or a HUP signal */
1087                 if (reload_config) {
1088                         struct udev_rules *rules_new;
1089
1090                         worker_kill(udev, 0);
1091                         rules_new = udev_rules_new(udev, resolve_names);
1092                         if (rules_new != NULL) {
1093                                 udev_rules_unref(rules);
1094                                 rules = rules_new;
1095                         }
1096                         reload_config = 0;
1097                 }
1098         }
1099
1100         udev_queue_export_cleanup(udev_queue_export);
1101         rc = 0;
1102 exit:
1103         udev_queue_export_unref(udev_queue_export);
1104         udev_rules_unref(rules);
1105         udev_ctrl_unref(udev_ctrl);
1106         if (pfd[FD_SIGNAL].fd >= 0)
1107                 close(pfd[FD_SIGNAL].fd);
1108         if (worker_watch[READ_END] >= 0)
1109                 close(worker_watch[READ_END]);
1110         if (worker_watch[WRITE_END] >= 0)
1111                 close(worker_watch[WRITE_END]);
1112         udev_monitor_unref(monitor);
1113         udev_selinux_exit(udev);
1114         udev_unref(udev);
1115         udev_log_close();
1116         return rc;
1117 }